Pressure regulator for dispensing apparatus



June 29, 1965 w. B. KOCHNER 1' 3,191,616

PRESSURE REGULATOR FOR DISPENSING APPARATUS Filed Oct. 1'4",''1'"ea Nl/ENTOR:

REGINA L. KOCHNER ADMINISTRATRIX gm; W M

ATTORNEYS.

eduction flow therefrom.

3,191,616 PRESSURE REGULATOR FOR DISPENSING APPARATUS William B. Kochner, deceased, late of St. Louis, Mo., by

The present invention relates generally to a dispensing device, and more particularly to 'an improved valved dispenser head for pressurizing and regulating eduction flow from a liquid container of the type disclosed in R. S.

.Knapp et a1. Patent No. 2,842,293, having a common assignee herewith.

This application is a continuation-in-part of copending application Serial No. 842,730 filed September 28, 1959 for Dispensing Apparatus, now abandoned.

The sale of beer and similar ebullient liquids in relatively la ge containers, particularly gallon size, for home use necessitates the provision of a simple, efiicient and reliable dispensing means for providing a constant pressure on the beer within the container and for regulating It is desirable to provide dispensing means of this type wherein carbon dioxide pressurization by means of a pierceable bulb With'gas therein at very high pressures may be employed. Several difiicult problems arise, however, in attempting to adapt very high gas pressure bulb pressurization to the dispensing of readily foamable, ebullient liquids. Although pressure regulating means have been known for maintaining a relatively constant, predetermined supply pressure from such very high pressure bulbs, such as in Lamb Patent No.

2,649,661, the sudden high pressure surges which characterize the application of initial gas supply as the very high pressure bulb is pierced, or which may occur inadvertently from slight inaccuracy of operation of a pressure regulator, have resulted in a highly undesirable pres sure over-run and have caused excessive foaming when such ebullient liquids as beer are dispensed. In order to maintain a constant pressure on the liquid in an efficient manner throughout the. dispensing life of the container, it is necessary to prevent liquid from working its way up into the pressure regulating structure of the pressurizing means. It is also of importance to control the amount of foaming of beer and the like as a result of agitation and mixing during flow through the discharge valve means. Still further, it is important to eliminate pockets in the pressurizing and dispensing structures in which beer might be captured and become sour during storage.

It is a primary object of this invention, therefore, to provide a dispensing device of the type described having novel pressure regulator means for controlling initial pressure over-run, for providing a constant dispensing pressure, and for preventing liquid back-up.

It is another object to provide a dispensing device of the type described having a self-closing, manually-actuated push button type of valve for regulating dispensing flow through a spigot without excessive foaming.

It is a further object to provide a dispensing device of i the type described having a novel eduction tube for effecting a spiral fiow pattern to reduce discharge pressure and facilitate the control of foaming.

It is still another object to provide a dispensing device :of the typedescribed having a novel arrangement and orientation of parts to efiectively preclude liquid collec-' .tion in stagnant pockets and thereby avoidthe risk of sou-ring during storage.

With these and other objects in view, the invention consists in the construction, arrangement and combination United States Patent of the various parts of the dispensing apparatus whereby "ice the objects contemplated are obtained as hereinafter more fully set forth, pointed out in the claims and illustrated in the accompanying drawing, wherein:

FIGURE 1 is atop plan view showing a container having a pressurizing and dispensing device constructed in accordance with the present invention operatively mounted therewith;

FIG. 2 is a side elevational view of the assembly shown in FIGURE 1, with parts broken away and in section to show details of internal construction;

FIGURE 3 is a fragmentary vertical cross-sectional view taken substantiallyas indicated by the line 3-3 on FIGURE 2; and

FIGURES 4, 5 and 6 are vertical cross-sectional views taken substantially as indicated by the lines 1-4, 55, and 66 on FIGURE 1.

Referring now to the drawing, there is shown a container 10 of the type used for storing liquids and capable of being internally pressurized. The container 19 is formed with a generally cylindrical Side wall 12, and a bottom wall serving to support the container in a generally upright position when disposed on a supporting surface. The bottom wall is centrally upwardly dished at 14 in a spherically curved manner, and is annularly upwardly conical at 16, outwardly of the central convexity 14, to increase the strength of the container, to improve upright support stability, and to facilitate substantially complete fluid Withdrawal.

The container 10 provides a top wall centrally downwardly dished at 18, and annularly downwardly conical at 20 outwardly thereof, in a substantially complementary manne to the bottom wall for increased pressurized strength. A centrally disposed neck 22, terminating in an outwardly roled bead or curl 24, extends upwardly from the top wall portion 18. The neck opening permits the attachment of a closure cap, of the crown type for example, so that the container may be filled with draft beer or a carbonated beverage at a brewery or bottler, and thereafter capped for storage and subsequent distribution. The cap may then be removed by the consumer at some convenient time of use, and a dispenser assembly providing pressurizing means and valve-re ulated spigot means attached by insertion into the exposed neck opening. In this way, a single dispenser assembly may be interchanged and repeatedly used with numerous containers, and the containers may be distributed and sold -vides attachment means at its lower end for releasably securing the assembly in fixed relation within the neck of the container. A plurality of latch elements 34 are pivotally secured to the body 32 and cooperate with the out wardly rolled bead or curl 24 to secure the dispenser assembly to the container neck 22. The lower end of the body 24 provides a reduced diameter portion 36 adapted to be slidingly received within the open neck of the container. For attachment of the dispenser assembly 30 to the container 10, it is merely necessary to push the reduced portion 36 downwardly into the open neck of the container until the latch elements 34 snap over the neck curl 24. Reference may be made to said R. S. Knapp et .al. Patent No. 2,842,293 for a detailed description of the may be moved forwardly into the main body 32 by manually rotating the bulb holder 42. A retainer plug 46 cooperatingly receives the neck of the bulb 4d, and an O-ring as is provided for effecting a gas-tight seal. After sealing engagement of the bulb neck, continued forward movement of the bulb by manual screwing of the holder 42 will serve to effect a piercing of the forward end of the 4 bulb 40 is initially pierced and before the pressures stabilize within the chamber 54a and before container 14 reaches the desired regulated or operating pressure. The

bulb by a piercing pin Stlsupported Within the plug 4-6.

The piercing pin 50 provides a suitable gas flow passage therethrough, which communicates outwardly with the bulb interior and terminates inwardly at a valve seat 52 formed by the plug ea. In this way, the bulb 4% will first be sealed off and then pierced to effect delivery of the compressed gas therein to the valve seat 52.

A hollow and generally tubular regulator body 54 is defined by the main body 32, and the plug 46 provides an elongated collar 56 which extends into the interior of the body 54. Apiston 58 is slidably reciprocable within the body 54-, and an annular O-ring 60 provides a gas-tight pressure seal with the inner wall thereof. A cylindrical stem 62 of the piston 58 is slidably supported and guided within the plug collar d. Gasket means defined by an O-ring 64 provides a seal between the cylindricalstem 62 and the circular inner wall of the collar 56. A valve seal disc 66 is carried at the free end of the stem 62 and is adapted to cooperate with the valve seat 52 to effect closure of the gas supply conduit of the piercing pin 50. A biasing spring 58 normally urges the piston'58 forwardly toward a valve-open position.

An end plate 7% provides a removable closure for the body 54, and cooperates with the free or forward end wall of the piston 58 to define a pressure regulator outlet chamber 54a wherein gas is maintained at an intermediate pressure between the very high pressure of the gas of bulb 4t and the liquid dispensing pressure maintained in container 143. A damping spring 72 is positioned in the space between the end plate 7t? and the piston 58. The spring constant of the damping spring '72 is substantially greater than that'of the biasing spring 6%. The valve members 52 and 66 are in normally closed relation by reason of the gas pressure existing in intermediate chamber 54a and the greater effective working area of the piston 58 with respect to the valve member 66. An adjustable stop member 7a is threadedly received within the end plate 7% and provides a free end portion which is adapted to be engaged by the piston 58. A cross-bore 76 is formed in the piston stem 62, and communicates with a longitudinal bore 78 for gas by-pass flow extending through the piston 58 to its free face end in flow communication with the intermediate chamber 54a. The free end of the adjustable stop 74 is provided with suitable transverse slots 89 to avoid obstruction of flow through the passage '73 when the piston 58 is in seated engagement against the stop 74, as in the position shown in FIGURE 6 of the drawing. A sealing plug 82 insures tamperproof assembly of the parts with the adjustable stop 74 in a predetermined selected position.

between the elongated shank or stem 62 and the collar 56 intermediate the valve seat 52 and the sealing ring 64. The restricted annular sliding space between the stem 62 and collar 56 provides relatively large resistance to gas flow and this operates to materially reduce the gas pressure from the very high pressure source bulb 4%. Gas at reduced pressure will then flow through the cross-bore or: transverse bore 7 6 and through longitudinal bore 78 to the pressure regulators outlet, intermediate-pressure chamber 54a. The spring 63 exerts a biasing force which will effect opening of the valve elements 52 and 66 when the intermediate pressure in the chamber 54a falls below that needed to maintain the constant pressure desired within the container 19 for dispensing-operation. The damping spring 72 modulates movement of the piston away from the valve seat and serves to prevent bouncing of the piston stern 62 and its valve disc 66 when the no as to obtain proper operation.

I dispensed.

adjustable stop 74 permits thevarious parts to be adjusted The selection of the space or gap between the f ee end of the stop 74 and the free end of the piston 58 provides additional means for effecting gas pressure reduction from the very high pres 'sure of bulb 4-6, by limiting the opening or movement of the valve dlSQ' fromvalve seat 52.

, A gas inlet duct 554 communicates at its one end with the chamber 54a and provides at its other end a threaded bore 86 in which a check valve screw 38- is received. A

longitudinal bore as and intersecting cross bore 92 are formed in the screw 88. A resilient sleeve 94 normally tightly surrounds the outer end of the screw 3?. When there is demand for pressurizing gas from container 10, pressure gas flows from the duct 8 t and through the bores and 92 will overcome the bias of sleeve 94 to effect escape between the outside Wall surface of the screw 38 and the inner wall surface of the sleeve 94. The resilient strength of the sleeve fi l is selected so as to, permit it to expand under a preselected pressure differential to thus provide an opening for the gas to pass into the container When the normal equilibrium pressure differential is reached on both sides of the check valve screw 88, the sleeve 94 will again tightly engage about the screw 88 to prevent further gas flow.

it is particularly important that the check valve means 38 and 9'4 be disposed substantially entirely within the main body 32 and within the neck 22 of the container Ill so as to be entirely above the surface of the liquid to be In addition, the enlarged head end of the screw 88, and the engagement of the free end of the resilient sleeve 94; against the annular shoulder defined by the :screw 38 intermediate its head and its shank, serves to effect a lateral direction of the incoming gas flow. In this way, the liquid within the container it), particularly in the case of beer or the like, .will not be disturbed by a high velocity incoming gas flow, thus avoiding the risk of foaming.

A flexible syphon tube 1%, preferably of suitable plastic material, reaches at its lower end to the container bottom, and is attached at its upper end to a shank H92 in a gas tight manner to prevent gas above the surface of liquid within the container from seeping therebetween and cause foaming of the liquid being dispensed. The tube 10%) has a weighted lower end 1 2M which remains at all times closely adjacent the container bottom wall within the annular pocket formed between portions 14 and 16 thereof, so as to permit substantially complete emptying of liquid from the container. A sleeve ills of suitable deformable plastic material, such as polyethylene or the like provides a fluid tight coupl ng between the syphon tube tilt and the shank 162. The shank 1 132 defines a vertically upwardly extending flow passage iii? having an outwardly downwardly inclined portion 10? which communicates at its outermost end with an enlarged flow chamber 11%. A faucet body 112 provides a sharply downwardly inclined discharge spout 11 i communicating at its inner end with the chamber 116. A fully rounded valve seat 116 is internally defined by the faucet body 112 at the outlet end of the chamber llltl.

A self-closing push button type of control valve is provided for regulating flow of liquid from the container 16 through the spout 114. The control valve comprises a stem 118 and a valve head 120 of rubber or synthetic resinous material, which is slidably reciprocable within the faucet body 112 and is adapted toseal against the rounded valve seat 116. A push button 122 having packing means 124 and biasing spring 126 enables manual flow-opening movement of the valve seatlZt) away from the valve seat 114 for discharge flow through the faucet body 112. The push button 122 is recessed within the faucet body 112 to avoid the risk of accidental valve opening, and a pair of external finger grips 125 and 127 are provided to facilitate manual actuation.

It is a highly important feature of the present invention that a rod 128 of particular form and function is disposed at the lowermost or inlet end of the syphon tube 100 and within the flow passage defined thereby, as best seen in FIGURE 3 of the drawing. The rod 128 is suitably slotted at the inlet end of the syphon tube 100 to permit dispensing flow upwardly into the tube 100 through the annular conduit space defined between the outer surface of the rod 128 and the inner surface of the tube 100. The function of the rod 128 is to impart a spiral flow pattern to the liquid as it moves upwardly through the tube 190. trated in FIGURE 3, a spiral wire element 130 surrounds the rod 128, and the rod is formed with a slight upward taper. In this way, the liquid will be forced to move through a tortuous or spiral path. It will be understood that a variety of structural equivalents may be utilized to achieve this same function, and the use of such embodiments is contemplated as a one-piece rod having an external spiral groove or land cut therein and disposed in closely adjacent or contacting relation to the inner wall surfaces of the tube 109. It will also be understood that the spiral flow imparting means may also be disposed at a point upwardly within the tube 100, rather than at the inlet end as shown. It is important, however, that such means be readily removable to facilitate cleaning and replacement.

Safety valve means are provided in the event that damage to the pressure regulator structure should prevent its proper functioning and risk excessive pressurization of the container 10. As best seen in FIGURE 5, a passageway 132 communicates with the interior of the container 1t) and with a vent chamber 134. A valve seat 136 is defined intermediate the passage 132 and chamber'134. A valve block 138 carries an O-ring 140 adapted to effect sealing engagement with the seat 136. A retaining screw 142, having a vent Opening 143, provides support means for a biasing spring 144 which operates to shift the block 138 toward a position of seating engagement of the O-ring 140 on the valve seat 136. The particular biasing strength of the spring 144 will serve to maintain sealing closure of the safety valve until a predetermined dangerous pressure has been reached, at which point safety relief flow will be enabled by valve unseating.

In the practical operation of the structure disclosed 'herein, various major problems which characterize the handling of such readily foamable liquids as beer and the like are effectively eliminated or minimized. When the dispenser assembly 30 has been secured toa fresh container of beer to be dispensed, the bulb 49 will be manually energized by movement into its piercing posi-- The initial sharp forward movement of the valve means effects a shifting of the piston 58 which is in turn damped by the spring 72 and controlled in extent by the adjustable stop, 74 to achieve an optimum piston action for the desired operating pressures.

Prior known structures have been subject to a back flow of liquid from the container interior upwardly through the pressurizing passageways into the pressure regulator valve structure. In order to solve this problem, there is provided a novel check valve which permits In the specific structure illusitself.

6 gas to flow into the container at the required pressurizing level, but which prevents any reverse flow. In particular, there is utilized the novel screw and sleeve structure 88-94 for accomplishing this objective.

Inordinate foaming is a very serious problem in any dispensing structures to be used with such liquids as beer. It has been discovered that it is a critical and essential requirement that the pressure at the discharge faucet be lower than the pressure within the container The novel use of spiral flow imparting means within the syphon tube serves to achieve this necessary pressure reduction between the container interior and the faucet spout.

A further requirement for a dispenser of the type dis closed, wherein a liquid which is subject to spoilage is to be stored and dispensed, is to prevent pockets of the liquid from being trapped and permitted to lie stagnant in the dispenser structure. This problem is particularly present within the discharge head or faucet spout. It is particularly important, therefore, that the entire faucet head 112 be disposed at a slightly downwardly inclined angle relative to the horizontal, and that all flow passages downstream of the dispensing valve means 116 120 be abruptly slanted so that no fluid will be retained outwardly of the valve seat where it would risk becoming sour. For this purpose the inclined passages 109 and 114 are provided.

The structure of the present invention provides a readily attached and detached dispenser device capable of providing efficient and uniform dispensing of beer and other ebullient liquids and of permitting their refrigjerated storage over a substantial time for periodic dispensing. While there has been shown and described, a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing tor comprising, in combination: a hollow regulator body,

means defining a valve seat that is adapted to communicate with a source of high pressure gas, a piston member freely and slidingly reciprocable within said hollow body in sealing relationship therewith to partially define a pressure outlet chamber spaced from said valve seat and adapted to be communicated with the interior of a container of ebullient liquid, an elongated annularcollar surrounding said valve seat and extending toward said piston member, said piston member carrying a valve member having an elongatedfshank whose cross-section is similar to but only slightly less than the interior crosssection ofthe annular collar so as to be slidably disposed in said collar and to define a sliding space of restricted cross-section that offers relatively large resistance to gas flow therethrough, and the extended terminus of said shank .being adapted for sealing engagement with the valve seat, gasket means carried on said elongated shank and slidably engaging said collar for effecting a seal therebetween for all positions of said piston member, by-pass conduit means for communicating gas under pressure from the sliding space region spaced axially between said gasket means and said valve seat to said pressure outlet chamber, thereby exposing the piston member to gas pressure that urges the valve member toward sealing engagement with the valve seat, and a coil spring surrounding the collar and engaging the piston member for automatically urging the piston member away from said valve .seat when'the gas pressure in said pressure'outlet chamber falls below a predetermined level.'

2. An improved pressure regulator for use with a container 'for ebullient liquid that utilizes a source of high pressure gas to effect pressurized selective flow of the ebullient liquid from the container; said pressure regulator comprising, in combination: a hollow regulator body, means defining a valve seat that is adapted to communicate with a source of high pressure gas, a piston member freely reciprocable within said hollow body in sealing relationship therewith to partially define a pressure outlet chamber spaced from said valve seat and adapted to be communicated with the interior of a container of ebullient liquid, an elongated annularcollar surrounding said valve seat and extending toward said piston, said piston carrying a valve member at one end thereof slidably disposed'in said collar, said valve member and said collar defining therebetween a sliding space of restricted cross-section that offers relatively large resistance to gas flow therethrough,

, said valve member being adapted for sealing engagement with the valve seat, by-pass conduit means including a transverse passageway in said valve member communicating with the sliding space between the valve member and cluding gasket means on said valve member slidingly engaged with the interior of said annular collar and being disposed further from the end of the valve member than the transverse passageway communicating with said sliding space for efiecting a seal between the valve member and the collar, whereby a preliminary pressure reduction of the gas is effected as the gas flows through said sliding space from the valve seat and into the transverse passageway.

4. A pressure regulator assembly comprising a main body having a flow chamber, a piston slidably mounted in said flow chamber in gas sealing relationship therewith, a damping spring mounted within said flow chamber to one side of said piston, an insert carried by said main body and defining a guide collar which projects into said flow chamber to the other side of said piston, said insert having a restricted flow passageway therethrough forming a valve seat at one end, a gas bulb piercing pin carried by said insert at the other end of the flow passageway and having a passageway therethrough and adapted for passing gas under pressure from a bulb through said flow p'assageway, a stem on said piston received in said guide collar and defining therewith a restricted flow space, 'a valve on the end of said stem cooperating with the seat for closing said flow passageway, a coil spring surrounding said collar and seated between said other side of said piston and said insert for normally biasing said valve towards its open position,.a seal engaged between said collar and stem for preventing gas flow therebetween the portion of the stem between the seal and valve slidingly cooperating with the guide collar, a pair of intersecting passageways in said stem and passing through the piston communicating said portion of the stem with said one side of the piston for conducting gas from said flow passageway through said restricted flow space, to the interior of the flow chamber on said one side of the piston, and an outlet from said flow chamber at said one side of the piston.

5. An improved pressure regulator for use with a container for ebullient liquid that utilizes a source of high pressure gas to effect pressurized selective flow of the 7 8 ebullient liquid from the container; said pressure regulator comprising, in combination: hollow regulator body means defining a gas inlet for communicating a source of high pressure gas thereinto and an outlet for gas therefrom at a reduced pressure adapted to be supplied to the container of ebullient liquid, said regulator body means'defining an inlet valve seat surrounding said inlet, an elongated collar member surrounding said inlet valve seat and arranged to communicate with said gas inlet, and a reduced-secondary-pressure chamber bounded in part by an elongated cylindrical Wall of greater inner diameter than the inner diameter of said elongated collar; and two-stage pressurereduction means for reducing the source of high pressure collar and to define a sliding space of restricted cross-section that ofiers relatively large resistance to gas flow therethrough, means at one end of the elongated shank being constructed and arranged for sealing engagement with the inlet valve seat, gasket means carried on said elongated shank and slidably engaging the collar for effecting a seal therebetween, a piston movable with said elongated shank and slidingly reciprocable within the elongated cylindrical wall portion of the reduced-socondary-pressure chamber with one side of the piston exposed to the pressure in said chamber, and by-pass conduit means for communicating the gas under pressure from thesliding space region located between the inlet valve seat and the said gasket means to said reduced-secondary-pressure chamber, the

pressure in said reduced-Secondary-pressure chamber acting against the piston to tend to move said piston and thereby said shank toward the valve seat for cutting off high pressure gas flow through said inlet, and the secondstage means of said pressure-reduction means including a flexible resilient member that is exposed to the pressure in the chamber of reduced-Secondary-pressure and being arranged and constructed to control gas flow from said chamber through said outlet for the gas.

6. A device as in claim 5 including spring means for normally biasing the shank away from the inlet valve seat.

7. A device as in claim 5 including a stop means on said regulator body means for preventing too great movement by the piston and shank away from the valve seat upon initial application of a high pressure gas source to the inlet of the improved pressure regulator.

8. A device as in claim 5 including spring means for damping the movement of the piston and shank away from the inlet valve seat.

9. A device as in claim 5 wherein the flexible resilient f member is constructed and arranged to serve as a check valve to prevent pressurized ebullient liquid from entering the reduced-secondary-pressure chamber of the pressure regulator.

References (Jilted by the Examiner UNITED STATES PATENTS 762,274 6/G4 Bourseau 137-50525 2,917,073 12/59 Dinkelkamp 137505.25 XR 3,004,686 10/61 McKee 137505.25 XR 'WILLIAM F. ODEA, Primary Examiner. ISADOR WEIL, Examiner.- I 

1. AN IMPROVED PRESSURE REGULATOR FOR USE WITH A CONTAINER FOR EBULLIENT LIQUID THAT UTILIZES A SOURCE OF HIGH PRESSURE GAS TO EFFECT PRESSURIZED SELECTIVE FLOW OF THE EBULLIENT LIQUID FROM THE CONTAINE; SAID PRESSURE REGULATOR COMPRISING, IN COMBINATION: A HOLLOW REGULATOR BODY, MEANS DEFINING A VALVE SEAT THAT IS ADAPTED TO COMMUNICATE WITH A SOURCE OF HIGH PRESSURE GAS, A PISTON MEMBER FREELY AND SLIDINGLY RECIPROCABLE WITHIN SAID HOLLOW BODY IN SEALING RELATIONSHIP THEREWITH TO PARTIALLY DEFINE A PRESSURE OUTLET CHAMBER SPACED FROM SAID VALVE SEAT AND ADAPTED TO COMMUNICATE WITH THE INTERIOR OF A CONTAINER OF EBULLIENTLIQUID, AN ELONGATED ANNULAR COLLAR SURROUNDING SAID VALVE SEAT AND EXTENDING TOWARD SAID PISTON MEMBER, SAID PISTON MEMBER CARRYING A VALVE MEMBER HAVING AN ELONGATED SHANK WHOSE CROSS-SECTION IS SIMILAR TO BUT ONLY SLIGHTLY LESS THAN THE INTERIOR CROSSSECTION OF THE ANNULAR COLLAR SO AS TO BE SLIDABLY DISPOSED IN SAID COLLAR AND TO DEFINE A SLIDING SPACE OF RESTRICTED CROSS-SECTION THAT OFFERS RELATIVELY LARGE RESISTANCE TO GAS FLOW THERETHROUGH, AND THE EXTENDED TERMINUS OF SAID SHANK BEING ADAPTED FOR SEALING ENGAGEMENT WITH THE VALVE SEAT, GASKET MEANS CARRIED ON SAID ELONGATED SHANK AND SLIDABLY ENGAGING SAID COLLAR FOR EFFECTING A SEAL THEREBETWEEN FOR ALL POSITIONS OF SAID PISTON MEMBER, BY-PASS CONDUIT MEANS FOR COMMUNICATING GAS UNDER PRESSURE FROM THE SLIDING SPACE REGION SPACED AXIALLY BETWEEN SAID GASKET MEANS AND SAID VALVE SEAT TO SAID PRESSURE OUTLET CHAMBER, THEREBY EXPOSING THE PISTON MEMBR TO GAS PRESSURE THAT URGES THE VALVE MEMBER TOWARD SEALING ENGAGEMENT WITH THE VALVE SEAT, AND A COIL SPRING SURROUNDING THE COLLAR AND ENGAGING THE PISTON MEMBER FOR AUTOMATICALLY URGING THE PISTON MEMBER AWAY FROM SAID VALVE SEAT WHEN THE GAS PRESSURE IN SAID PRESSURE OUTLET CHAMBER FALLS BELOW A PREDETERMINED LEVEL. 